Back to EveryPatent.com
United States Patent |
5,308,513
|
Harmalker
,   et al.
|
May 3, 1994
|
Wash cycle or rinse cycle fabric conditioning compositions
Abstract
Fabric conditioning aqueous liquid emulsions are provided which impart
softness and antistatic properties to laundered fabrics as a wash-cycle
additive for through-the-wash use or alternatively as a rinse cycle
additive. The dispersed phase of the liquid emulsions comprise complexes
of specified tertiary amines and multi-functional carboxylic acids in
combination with unreacted amine and a minor amount of one or more
specified alkyl cellulose ethers to enhance high temperature emulsion
stability.
Inventors:
|
Harmalker; Subhash (Somerset, NJ);
Dixit; Nagaraj S. (Plainsboro, NJ);
Kinscherf; Kevin M. (Freehold, NJ)
|
Assignee:
|
Colgate-Palmolive Company (New York, NY)
|
Appl. No.:
|
021392 |
Filed:
|
February 23, 1993 |
Current U.S. Class: |
510/522; 510/328; 510/332; 510/527 |
Intern'l Class: |
C11D 003/22; C11D 001/40; C11D 001/65; D06M 013/342 |
Field of Search: |
252/174.17,8.8,544,525,8.6,174.19,DIG. 14,527,546
|
References Cited
U.S. Patent Documents
4136038 | Jan., 1979 | Pracht et al. | 252/8.
|
4808086 | Feb., 1989 | Evans et al. | 427/242.
|
4828722 | May., 1989 | Steltenkamp | 252/8.
|
4869836 | Sep., 1989 | Harmalker | 252/8.
|
4954270 | Sep., 1990 | Butterworth et al. | 252/8.
|
5009800 | Apr., 1991 | Foster | 252/8.
|
5160641 | Nov., 1992 | Foster | 252/8.
|
Foreign Patent Documents |
0267657 | May., 1988 | EP.
| |
0331237 | Sep., 1989 | EP.
| |
0340872 | Nov., 1989 | EP.
| |
2601390 | Jan., 1988 | FR.
| |
Other References
EP Search Report for EP 91 20 1908, Oct. 28, 1991.
Hackh's Chemical Dictionary, 4th ed. (1972), ed. Julius Grant, p. 240.
|
Primary Examiner: Lieberman; Paul
Assistant Examiner: Hertzog; Ardith
Attorney, Agent or Firm: Lieberman; Barnard, Sullivan; Robert C.
Parent Case Text
BACKGROUND OF THE INVENTION
This application is a continuation-in-part of U.S. Ser. No. 07/704,833
filed May 20, 1991 (now abandoned) which is a continuation-in-part of
07/555,683 filed Jun. 20, 1990, (now abandoned) the disclosures of which
are incorporated herein by reference.
Claims
What is claimed is:
1. A wash cycle or rinse cycle-additive aqueous liquid emulsion for
providing softness and anti-static properties to fabrics treated therewith
in a laundry bath without adversely affected fabric cleaning comprising:
(A) from about 1 to 30%, by weight of a particulate fabric conditioning
composition having a median particle diameter greater than about 10 and up
to about 50 microns comprising:
(a) a fabric conditioning amount of a multi-functional carboxylic acid
complex of a tertiary amine formed from the reaction of (i) and tertiary
amine having the general formula:
##STR4##
wherein R.sub.1 is methyl or ethyl, and R.sub.2 and R.sub.3 are each
independently an aliphatic group having from 12 to 22 carbon atoms, and
(ii) a multi-functional carboxylic acid selected from the group consisting
of citric acid, and di and tri carboxylic acids having from 21 to 54
carbon atoms;
(b) unreacted tertiary amine having the general formula defined above, said
unreacted amine being present in an amount of at least 0.2 times the
stoichiometric amount of tertiary amine required to form the
multi-functional carboxylic acid complex of (a); and
(c) a stabilizing amount from about 0.1 to 1% by weight of the aqueous
liquid emulsion, of an alkyl cellulose ether to substantially prevent
particle break-down of said particulate fabric conditioning composition,
said alkyl cellulose ether being selected from the group consisting of
methylcellulose, hydroxypropylmethyl cellulose and derivatives of
hydroxyethyl cellulose wherein the terminal hydrogen of the hydroxyether
group is replaced by an alkyl chain having from 10 to 24 carbon atoms, and
mixtures thereof, said alkyl cellulose ether having a molecular weight of
at least 25,000, the stabilizing amount of alkyl cellulose ether relative
to the fabric conditioning amount of carboxylic acid complex of a tertiary
amine defined in (a) being less than about 1:20, by weight, and which
stabilizing amount of cellulose ether provides no improved fabric
softening performance for said fabric conditioning composition, the
dispersed phase of the liquid emulsion being essentially comprised of said
particles of fabric conditioning composition;
(B) from about 0.1 to 10%, by weight of one or more emulsifying agents; and
(C) the balance water.
2. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 wherein the tertiary amine is methyl distearyl amine.
3. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 wherein the tertiary amine is methyl di(hydrogenated tallow) amine.
4. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 wherein R.sub.2 and R.sub.3 are each an alkyl group.
5. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 wherein the multifunctional carboxylic acid is citric acid.
6. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 wherein said unreacted amine is present in an amount of from about 0.3
to 6 times the stoichiometric amount of tertiary amine reacted to form
said complex.
7. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 wherein the fabric conditioning composition is present in an amount of
from about 5 to about 20%, by weight.
8. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 which further contains a compound for providing anti-static properties
additional to that provided by said fabric conditioning composition.
9. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 wherein the alkyl cellulose ether is present in an amount from about 0.1
to 0.5%, by weight.
10. A wash cycle or rinse cycle-additive liquid emulsion according to claim
1 wherein the viscosity of the aqueous liquid emulsion is substantially
unaffected by the presence of the alkyl cellulose ether.
11. A process for imparting softness and anti-static properties to fabrics
comprising the step of contacting the fabrics in a laundry wash or rinse
liquor with an aqueous liquid emulsion containing an effective amount of a
particulate fabric conditioning composition having a median particle
diameter greater than about 10 and up to about 50 microns comprising:
(a) a fabric conditioning amount of a multi-functional carboxylic acid
complex of a tertiary amine formed from the reaction of (i) a tertiary
amine having the general formula:
##STR5##
wherein R.sub.1 is methyl or ethyl, and R.sub.2 and R.sub.3 are each
independently an aliphatic group having from 12 to 22 carbon atoms, and
(ii) a multifunctional carboxylic acid selected from the group consisting
of citric acid, and di and tricarboxylic acids having 21 to 54 carbon
atoms;
(b) unreacted tertiary amine having the general formula defined above, said
unreacted amine being present in an amount of at least 0.2 times the
stoichiometric amount of tertiary amine required to form the
multifunctional carboxylic acid complex of (a); and
(c) an emulsion stabilizing amount from about 0.1 to 1% by weight of the
aqueous liquid emulsion of an alkyl cellulose ether selected from the
group consisting of methylcellulose, hydroxypropylmethyl cellulose and
derivatives of hydroxyethyl cellulose wherein the terminal hydrogen of the
hydroxyether group is replaced by an alkyl chain having from 10 to 24
carbon atoms, and mixtures thereof, said alkyl cellulose ether having a
molecular weight of at least 25,000, the emulsion stabilizing amount of
alkyl cellulose ether relative to the fabric conditioning amount of
carboxylic acid complex of a tertiary amine defined in (a) being less than
about 1:20, by weight, and which emulsion stabilizing amount of cellulose
ether provides no improved fabric softening performance for said fabric
conditioning composition.
12. A process in accordance with claim 11 wherein the multifunctional
carboxylic acid is citric acid.
13. A process in accordance with claim 11 wherein the tertiary amine is
methyl di (hydrogenated tallow) amine.
14. A process in accordance with claim 11 wherein the unreacted amine is
present in an amount of from about 0.3 to 6 times the said stoichiometric
amount.
15. A process for preparing a stable wash cycle or rinse cycle-additive
aqueous liquid emulsion according to claim 1 comprising the steps of:
(a) providing an aqueous liquid containing a mixture of (i) a fabric
conditioning amount of the multi-functional carboxylic acid complex of a
tertiary amine as defined in claim 1; (ii) unreacted tertiary amine as
defined in claim 1; and (iii) an alkyl cellulose ether as defined in claim
1;
(b) heating the aqueous liquid prior to or subsequent to step (a) to a
temperature sufficient to at least melt the mixture of carboxylic acid
complex and unreacted tertiary amine;
(c) introducing into said aqueous liquid a first portion of an emulsifying
agent, other than an alkyl cellulose ether said first portion being an
amount selected to form upon mixing with said aqueous liquid emulsified
particles containing components (i), (ii), and (iii) and having a median
particle diameter greater than about 10 microns;
(d) mixing the aqueous liquid with the first portion of emulsifying agent
to form an emulsion containing the aforesaid emulsified particles as the
dispersed phase;
(e) cooling the resulting emulsion to a temperature sufficiently below the
melting point of the particles formed in step (d) to at least partially
solidify said particles; and
(f) introducing into the emulsion following step (e) a second portion of
one or more emulsifying agents to adjust the HLB value of the emulsion to
that required for high-temperature phase stability.
16. A process in accordance with claim 15 wherein in step (a) the mixture
of carboxylic acid complex and unreacted amine is introduced into the
aqueous liquid at a temperature below its melting point and wherein
subsequent to step (a) said aqueous liquid is heated to a temperature
sufficiently above the melting point of the mixture.
17. A process in accordance with claim 15 wherein the tertiary amine in
said fabric conditioning composition is methyl di(hydrogenated) tallow
amine.
18. A process in accordance with claim 15 wherein the multifunctional
carboxylic acid in said fabric conditioning composition is citric acid.
19. A process in accordance with claim 15 wherein the amount of unreacted
tertiary amine in the aqueous liquid is from about 0.3 to 3 times the
stoichiometric amount of amine reacted to form the carboxylic acid
complex.
20. A process in accordance with claim 15 wherein the amount of unreacted
tertiary amine in the liquid is from about 5 to 30%, by weight, of said
liquid.
21. A process in accordance with claim 15 further including the step of
introducing a viscosity modifier and optionally other adjuvants into said
aqueous liquid.
22. A process in accordance with claim 15 wherein in step (d) the
emulsified particles of fabric conditioning composition have a median
diameter of from about 25 to 50 microns.
Description
This invention relates to novel aqueous liquid emulsions useful as
through-the-wash or rinse cycle-additive fabric conditioning compositions
and their method of manufacture, such fabric conditioning compositions
providing softening and antistatic benefits to laundered fabrics without
adversely affecting cleaning.
A large number of compositions have been disclosed which impart softening
and antistatic properties to laundered fabrics. Generally, these contain
cationic compounds, especially quaternary ammonium salts. Such
compositions are widely marketed for home use in the form of emulsions
which must be added to the washing machine during the rinse cycle. If the
emulsions are added during the wash cycle, the cationic fabric
conditioners may interact with anionic surfactants present in the washing
composition so as to render a portion of each of such cationic compound
and anionic surfactant unavailable for either cleaning or fabric
conditioning.
Another means of providing fabric conditioning which has attained some
commercial success is to add the conditioning agent while the clothes are
being machine dried.
While fabric conditioning during either the rinse and/or drying cycles can
be effective, both methods of conditioning are more inconvenient than a
through-the-wash method where the conditioning agent is added with the
detergent composition at the initiation of the wash cycle.
Compositions are known which can be added to a washing machine at the start
of the wash cycle and effectively provide fabrics with a detergency
treatment during the wash cycle and a fabric conditioning treatment during
either the rinsing operation or subsequently when the fabrics are heated
in a machine dryer. Compositions of this type are known in the art as
through-the-wash fabric conditioners. An important advantage of such
compositions is that they obviate the need for adding a separate fabric
conditioning product in the rinse cycle or in a machine dryer.
Through-the-wash type conditioning agents are well known in the art.
European Patent Application No. 0,123,400, published Oct. 31, 1984
discloses fabric conditioning agents comprising salts of specified
tertiary amines and carboxylic acids which are utilized in the form of
nodules which pass virtually unchanged through the wash and rinse and
condition the fabric when heated in a dryer. The nodules are meant to be
added to the laundry wash liquor at the beginning of the wash cycle along
with a conventional detergent. European Patent Publication No. 0,133,804
published Mar. 6, 1985 discloses detergent compositions containing clay
fabric softeners and particles of a complex of a long chain amine and a
fatty acid. U.S. Pat. No. 4,514,444 to Ives discloses a fabric
cleaning/conditioning composition comprising carboxylic acid salts of a
tertiary amine in combination with polyethylene glycol. U.S. Pat. No.
4,375,416 to Crisp et al. discloses a textile softening detergent
composition comprising a specified class of tertiary amines with a
smectite-type clay in a detergent composition such that softening benefits
are provided without impairing cleaning performance.
Other recent prior art relating to the field of the invention includes U.S.
Pat. No. 4,237,155 to Kardouche which discloses a dryer-added fabric
conditioning agent comprised of a carboxylic acid salt of a tertiary
amine. British Patent 1,514,276 discloses the use of tertiary amine
compositions as wash-cycle fabric softeners.
U.S. Pat. No. 4,808,086 to Evans et al discloses dryer-added fabric
conditioning articles comprised of a fabric softening agent and a soil
release agent which may be certain defined hydroxyethers of cellulose. The
soil release agent may be present in amounts up to 70%, by weight, of the
composition and preferably from about 25 to 50%.
European Patent Application 331,237 naming Butterworth et al as inventors
discloses fabric conditioning compositions containing a polymeric
thickener for fabric softening compositions. The polymeric thickeners are
hydrophobically modified cellulose ethers, and the preferred softening
materials are quaternary ammonium compounds. Insofar as conventional quat
rinse-cycle softening compositions have very low viscosities in the
absence of thickeners (i.e. generally about 30-40 cps.), the Butterworth
et al European patent seeks to provide a thickened quat softening
composition. Referring to Table 4 of the Butterworth et al European
Patent, for example, the unthickened control is shown to have a viscosity
of 5 which upon addition of a designated hydroxyethyl cellulose at weight
percents of 0.13 and 0.15%, respectively, is shown to be raised to 78 and
101, a viscosity increase of one order of magnitude. The carboxylic
acid-amine complexes of the present invention, on the other hand, are
relatively thick compositions at useful concentration of 5 to 10%, by
weight, having viscosities of about 500 cps. at room temperature. Hence,
the combination of carboxylic acid-amine complexes as herein described
with a thickener of any type is unnecessary and undesirable. By way of
comparison, the addition of an alkyl cellulose either to a fabric
conditioning composition in accordance with the invention provides
essentially no increase in viscosity to the resultant composition, and, in
some instances, even causes the viscosity to be lowered.
Complexes of specified tertiary amines and carboxylic acids have been
previously disclosed as through-the-wash fabric conditioners in U.S. Pat.
No. 4,828,722 to Steltenkamp. In U.S. Pat. No. 4,869,836 to Harmalker
there is described the combination of unreacted tertiary amine with a
complex of reacted tertiary amine and multi-functional carboxylic acid.
The resulting fabric conditioners are used advantageously in the form of
aqueous liquid emulsions. While these emulsions are generally effective
for fabric conditioning, they nevertheless are often destabilized or
suffer poor performance when subjected to extreme conditions, such as
elevated temperatures, i.e. above 110.degree. F. Consequently, there
remains a need for providing an effective fabric-conditioning liquid
emulsion capable of being used as either a wash-cycle or rinse-cycle
additive, and which is highly stable at elevated temperatures.
SUMMARY OF THE INVENTION
The present invention provides a wash cycle or rinse cycle-additive aqueous
liquid emulsion for providing softness and anti-static properties to
fabrics treated therewith in a laundry bath without adversely affecting
fabric cleaning comprising
(A) from about 1 to 30%, by weight of a particulate fabric conditioning
composition having a median particle diameter greater than about 10 and up
to about 50 microns comprising:
(a) a fabric conditioning amount of a multi-functional carboxylic acid
complex of a tertiary amine formed from the reaction of (i) a tertiary
amine having the general formula:
##STR1##
wherein R.sub.1 is methyl or ethyl, and R.sub.2 and R.sub.3 are each
independently an aliphatic group having from 12 to 22 carbon atoms, and
(ii) a multi-functional carboxylic acid selected from the group consisting
of citric acid, and di and tricarboxylic acids having from 21 to 54 carbon
atoms;
(b) unreacted tertiary amine having the general formula defined above, said
unreacted amine being present in an amount of at least 0.2 times the
stoichiometric amount of tertiary amine required to form the
multi-functional carboxylic acid complex of (a); and
(c) an emulsion stabilizing amount of an alkyl cellulose ether selected
from the group consisting of methylcellulose, hydroxypropylmethyl
cellulose and derivatives of hydroxyethyl cellulose wherein the terminal
hydrogen of the hydroxyether group is replaced by an alkyl chain having
from 10 to 24 carbon atoms, and mixtures thereof, said alkyl cellulose
ether having a molecular weight of at least 25,000, the emulsion
stabilizing amount of alkyl cellulose ether relative to the fabric
conditioning amount of carboxylic acid complex of a tertirary amine
defined in (a) being less than about 1:20, by weight, and which emulsion
stabilizing amount of cellulose ether provides no improved fabric
softening performance for said fabric conditioning composition, the
dispersed phase of the liquid emulsion being essentially comprised of said
particles of fabric conditioning composition.
(B) from about 0.1 to 10%, by weight of one or more emulsifying agents; and
(C) the balance water.
The most effective fabric conditioning compositions of the invention
contain an amount of unreacted tertiary amine varying from about 0.3 to 6
times the stoichiometric amount of reacted amine in the complex,
preferably from about 0.6 to 6 times the said stoichiometric amount.
Where, for example, the multi-functional carboxylic acid selected to form
the complex is citric acid, the stoichiometric amount of reacted amine in
the complex is 3 moles of amine per mole of citric acid.
The term "complex" as used throughout the specification and claims refers
to the reaction product of the above described tertiary amine and
carboxylic acid, and characterizes such reaction product in terms of the
primary constituent thereof which is a complex rather than a salt of the
acid and amine. The basis of such characterization is explained
hereinafter in the specification. Although the applicant does not wish to
be limited by any theory regarding the nature of such reaction product, it
is believed to be an equilibrium mixture comprised of the acid-amine
complex (about 80%, by weight) and the acid-amine salt (about 20%, by
weight). Accordingly, as used herein, the term "complex" includes both the
acid-amine complex formed by the reaction of the tertiary amine and
carboxylic acid as well as the relatively minor amount of salt in
equilibrium therewith.
In accordance with a preferred embodiment of the invention, the aqueous
liquid emulsion contains adjuvants such as perfumes, colorants,
brighteners, foam stabilizers and the like and, optionally further
includes an antistatic composition distinct from the defined fabric
conditioning composition to enhance the anti-static properties of the
liquid emulsion. A preferred additional anti-static composition for this
purpose is tallow neodecanamide.
In accordance with the process aspect of the invention, softness and
anti-static properties are imparted to fabrics by contacting such fabrics
in a laundry bath or rinse liquor with an aqueous liquid emulsion
containing an effective amount of a particulate fabric conditioning
composition having a median particle diameter greater than about 10 and up
to about 50 microns, which fabric conditioning composition comprises:
(a) a fabric conditioning amount of a multi-functional carboxylic acid
complex of a tertiary amine formed from the reaction of (i) a tertiary
amine having the general formula:
##STR2##
wherein R.sub.1 is methyl or ethyl, and R.sub.2 and R.sub.3 are each
independently an aliphatic group having from 12 to 22 carbon atoms, and
(ii) a multi-functional carboxylic acid selected from the group consisting
of citric acid, and di and tricarboxylic acids having from 21 to 54 carbon
atoms;
(b) unreacted tertiary amine having the general formula defined above, said
unreacted amine being present in an amount of at least 0.2 times the
stoichiometric amount of tertiary amine required to form the
multi-functional carboxylic acid complex of (a); and
(c) an emulsion stabilizing amount of an alkyl cellulose ether selected
from the group consisting of methylcellulose, hydroxypropylmethyl
cellulose and derivatives of hydroxyethyl cellulose wherein the terminal
hydrogen of the hydroxyether group is replaced by an alkyl chain having
from 10 to 24 carbon atoms, and mixtures thereof, said alkyl cellulose
ether having a molecular weight of at least 25,000, the emulsion
stabilizing amount of alkyl cellulose ether relative to the fabric
conditioning amount of carboxylic acid complex of a tertiary amine defined
in (a) being less than about 1:20, by 7eight, and which emulsion
stabilizing amount of cellulose ether provides no improved fabric
softening performance for said fabric conditioning composition.
Although the applicants do not wish to be bound by any theory of operation,
it is believed that the alkyl cellulose ether incorporated into the liquid
emulsion of the invention forms at least a partial coating upon the
particles of fabric conditioning composition which are formed upon
emulsification. This coating appears to substantially prevent particle
break-down over a wide range of temperatures as well as the undesired
subsequent coalescence of smaller particles of acid-amine complex into
larger aggregate particles, a problem characteristic of liquid emulsions
known in the art containing particulate complexes of carboxylic acid and
amine which are typically susceptible to high temperature breakdown and
concomitant product separation. It has further been discovered that for
particulate compositions having a median particle diameter above about 10
microns, and more preferably at median particle sizes from about 25 to 50
microns, the fabric conditioning, physical stability and flow
characteristics of the resulting liquid emulsion are at an optimum.
Accordingly, for the fabric conditioning compositions of the invention the
desired range of particle size is able to be maintained over a broad range
of temperature extending from ambient to above the melting point of the
carboxylic acid-amine complex, typically about 110.degree. F.
The alkyl cellulose ether as used herein provides no fabric softening
benefit to the fabric conditioning composition.
DETAILED DESCRIPTION OF THE INVENTION
The fabric conditioning compositions of the invention are comprised of
three essential components. The first and second components are,
respectively, a complex of tertiary amine with a multi-functional
carboxylic acid as herein defined and unreacted tertiary amine. The
suitable tertiary amines are represented by the general formula
##STR3##
wherein R.sub.1 is methyl or ethyl, and R.sub.2 and R.sub.3 are each
independently an aliphatic group having from 12 to 22 carbon atoms.
Examples of preferred amines include methyl distearyl amine, ethyl
distearyl amine, methyl di(hydrogenated tallow) amine, ethyl
di(hydrogenated tallow) amine, methyl diolelylamine, methyl dicoconut
amine, methyl dilaurylamine, and methyl dipalm oil amine.
The multi-functional carboxylic acid utilized in the present invention is
selected from among citric acid and di and tri carboxylic acids having 21
to 54 carbon atoms. Most preferred for use herein is citric acid. Among
the other preferred acids are a dicarboxylic acid having 21 carbon atoms
e.g. 5 (or 6)-carboxy-4 hexyl-2-cyclohexene-1-octanoic acid (sold
commercially under the tradename Westvaco Diacid 1550 by Westvaco
Corporation): dimerized oleic acid (sold commercially under the tradename
Dimer Acid by Emery Industries); and a C.sub.54 trimer of oleic acid.
The amine-multifunctional carboxylic acid complexes of the invention are
generally prepared by forming a mixture of amine and multicarboxylic acid,
preferably in a molar ratio of amine to carboxylic acid above that
required for the stoichiometric reaction so as to provide the desired
amount of unreacted amine in the reaction product, and heating such
mixture to a temperature sufficient to form a melt.
For the example of a tertiary amine having a melting point below that of
the carboxylic acid, preparation is conveniently effected by first heating
the amine to its melting point (generally about 35.degree. to 45.degree.
C.) and then adding thereto the multicarboxylic acid, such as for example
citric acid, in the form of a solid. The resulting mixture is then heated
to a temperature below the melting point of the carboxylic acid, but
sufficient to form a molten mixture. In the case of citric acid, heating
the reactant to a temperature of about 115.degree. C. for about five to
ten minutes will form a molten mixture having a melting point (about
50.degree. C.) intermediate of the citric acid and the amine. The molten
mixture comprises the reaction product of amine-multicarboxylic acid
complex in equilibrium with a minor amount of amine-carboxylic acid salt.
In an alternate embodiment, the amine and carboxylic acid are reacted in a
stoichiometric ratio to form the complex followed by the addition of
unreacted tertiary amine to the resulting reaction product. This
embodiment is particularly advantageous where it is desired to employ an
unreacted amine in the fabric condition composition which is different
from the reacted amine. This may be desirable in some instances for
purposes of economy.
The determination of the nature of the reaction product can be illustrated
in terms of the reaction between methyl di(hydrogenated tallow) amine and
dimerized oleic acid which were mixed and heated following the general
procedure described above except that in this instance the amine having a
melting point above the carboxylic acid is added in solid form to
dimerized oleic acid which is liquid at ambient temperature. The resulting
reaction product was identified as a weak hydrogen bonded complex (80 wt.
%) in equilibrium with the corresponding salt (20 wt. %). Identification
was based on measurements involving melting points and spectroscopic
techniques. The complex melted at 28.degree. to 31.degree. C. which is
intermediate between the melting point of the amine (34.degree. to
38.degree. C.) and the carboxylic acid (4.degree. to 5.degree. C.). This
indicates the formation of a complex rather than an amine salt, the latter
being characterized by a sharp melting point higher than the corresponding
amine.
The Infra red spectrum of the complex shows the presence of two moderate
carbonyl bands at wavelengths of 1709 cm.sup.-1 and 1550 cm.sup.-1. The
935 cm.sup.-1 wavelength indicative of H-bonding of the particular free
carboxylic acid is absent, indicating the presence of a complex rather
than salt formation. By means of ESCA (Election Spectroscopy for Chemical
Analysis) measurements, it was determined that the reaction product was
about 20% amine salt and 80% of the amine-carboxylic acid complex. The
chemical shift of the ionic nitrogen of the salt was different than that
of the neutral nitrogen of the complex. The relative amounts of these two
nitrogen signals provide the basis for determining the relative amount of
amine salt versus amine complex.
An alkyl cellulose ether is the third essential component of the
particulate fabric conditioning composition. Suitable alkyl cellulose
ethers are selected from among methylcellulose and hydroxypropylmethyl
cellulose, sold under the trademark "Methocel" by Dow Chemical Company;
hydroxypropylcellulose, sold under the trademark "Klucel" by Hercules
Chemical Company; and derivatives of hydroxyethyl cellulose (HEC) wherein
the terminal hydrogen of the hydroxyether group is replaced by an alkyl
chain having from 10 to 24 carbon atoms, such HEC derivatives being sold
under the trademark "Natrosol Plus" by Hercules Chemical Company, and are
extensively described in U.S. Pat. No. 4,228,277 issued Oct. 14, 1980. The
amount of alkyl cellulose ether present in the particulate fabric
conditioning composition is generally from about 0.1 to 5%, by weight, of
the aqueous liquid emulsion, and preferably, from about 0.1 to 1%, by
weight, and most preferably from about 0.1 to 0.5% in order to provide the
requisite high temperature stability to the particles of fabric
conditioning composition. It is believed that the alkyl cellulose ether
must be of sufficient viscosity in the emulsion to deposit on the surface
of the emulsion particles and form an elastic film or coating thereon.
Hence, the molecular weight of the cellulose ether required for this
stabilizing purpose is at least 25,000 and preferably at least 30,000.
The aqueous liquid emulsion of the invention may be advantageously added to
the laundry bath or to the rinse liquor independent of any laundry
detergent composition or may conveniently be added to the laundry bath
during the wash cycle in conjunction with a liquid or granular detergent
composition.
The method of preparation of the aqueous emulsion is predicated upon
forming an emulsion or suspension which is stable over a practical range
of temperatures, and particularly at high temperature, namely, it does not
undergo phase separation at temperatures up to about 120.degree. F., and,
in addition, the particles of fabric conditioning composition which
comprise the dispersed phase of the emulsion must be of the requisite size
to deposit on washed fabrics during the wash cycle. It has been discovered
that when present in an emulsion at particle sizes having a median
diameter above about 10 microns, preferably from about 25 to 100 microns,
and most preferably from about 25 to 50 microns, the composition of the
invention is capable of providing effective softening and anti-stat
properties to washed fabrics whereas at particles sizes below such value
fabric conditioning is often adversely affected. Although the applicant
does not wish to be bound by any theory, it is believed that particle
sizes of above about 10 microns are required in order to effect deposition
of said particles on fabrics in the wash water, such particle size
limitation not being critical for rinse cycle softening.
To insure high temperature stability and the avoidance of phase separation,
the HLB (hydrophilic-lipophilic balance) value of the emulsion is
preferably regulated to within a predetermined range required for
stability by the addition of suitable emulsifying agents. The required
range of HLB is readily determined by trial and error for each particular
combination of tertiary amine and carboxylic acid utilized in the
composition of the invention. For the particular instance where citric
acid and methyl di(hydrogenated tallow) methyl amine are used to form the
fabric conditioning composition, the HLB of the emulsion must be from
about 11.5 to 12.5 to achieve the desired high temperature stability.
The liquid emulsion compositions preferably contain from about 5 to about
30%, and most preferably from about 7 to about 20% of the fabric
conditioning composition of the invention, based on the total weight of
the emulsion composition. At such concentrations, an effective amount of
fabric conditioning composition is provided to the wash fabric when
dispensing an amount of the liquid emulsion to the wash or rinse cycle of
an automatic washing machine comparable to the amounts added by users of
commercial liquid fabric conditioners.
Nonionic surfactants are among the preferred emulsifying agents for
preparing an emulsion in accordance with the invention having the desired
stability, viscosity and particle size of fabric conditioning composition
in the dispersed phase. Among the useful emulsifying agents are Neodol
25-3 (an ethoxylated alcohol sold by Shell Chemical Company comprising a
fatty alcohol averaging about 12 to 15 carbon atoms with about 3 moles of
ethylene oxide per mole of alcohol); Neodol 25-12; and Neodol 45-13.
Neodol 25-3 and 45-13 are particularly preferred for this purpose.
The preparation of the emulsion is conveniently effected in three stages:
in the first stage the fabric conditioning composition, preferably at a
temperature above its melting point, is added to an aqueous liquid,
preferably water, along with a first portion of an emulsifying agent, such
first portion being an amount selected to form upon mixing with the fabric
conditioning composition particles of emulsified fabric conditioning
composition having a median diameter above about 10 microns. The order of
addition of the fabric conditioning composition and the first portion of
emulsifying agent is not critical. It is preferred that the aqueous liquid
be preheated to a temperature corresponding to at least the melting point
of the fabric conditioning composition if the latter is introduced as a
liquid. This is to insure that the emulsified particles formed in the
first stage are in liquid form. In an alternate embodiment, the fabric
conditioning composition is introduced into the aqueous liquid as a solid,
following which the liquid is heated to a temperature sufficiently above
the melting point of the conditioning composition such that upon mixing
the conditioning composition with the first portion of emulsifying agent,
there is provided an emulsion containing as the dispersed phase liquid
particles of fabric conditioning composition having the desired particle
size.
In the second stage the resulting emulsion is cooled to a temperature
sufficiently below the melting point of the fabric conditioning
composition so as to at least partially solidify the emulsified particles
and form a suspension of solid particles in the aqueous liquid. In the
third stage, a second portion of one or more emulsifying agents is added
to the emulsion or suspension formed in the second stage so as to adjust
the HLB value to that required for high temperature stability. This HLB
value can be conveniently determined by a simple trial and error
technique. As defined herein, the characterization of "high temperature
stability" for a liquid emulsion in accordance with the invention refers
to its being able to be maintained at 120.degree. F. for at least 24 hours
without the occurrence of phase separation. After the formation of the
emulsion in the third stage, electrolytes such as calcium chloride
dihydrate, or sodium chloride may be added as viscosity modifiers, if
needed, as well as defoaming materials to enhance proper mixing of the
components by inhibiting phase separation resulting from foam agitation.
Other optional components include colorants and perfume which are
advantageously added sequentially under agitation.
The emulsified particles in the dispersed phase of the emulsion are not all
of uniform size and comprise a broad distribution of particle sizes, but
it is required that the median diameter of such particles be above 10
microns. A preferred particle size is that having a mean diameter of from
about 25 to 50 microns. Measurement of the emulsified particles is most
conveniently carried out at the end of the third stage when the final
emulsion is formed rather than at the end of the first stage where the
relatively strong association of the emulsified particles may make the
particle size measurement somewhat less accurate.
The aforementioned three-stage method of preparation is predicated upon
utilizing a fabric conditioning composition having a melting point above
ambient temperature such that in the first stage of preparation only a
limited amount of emulsifying agent is added to provide the desired size
of emulsified particles as a dispersed liquid phase. Thereafter upon
cooling, the dispersed particles solidify, allowing additional amounts of
emulsifying agent to be added to the emulsion without causing any
diminution in particle size. Thus, the HLB of the emulsion can be
independently adjusted to the desired range without affecting the size of
the particles in the dispersed phase.
EXAMPLE 1
A liquid emulsion in accordance with the invention was prepared as follows:
To 0.3 grams of Methocel A4C.sup.R, a methylcellulose marketed by Dow
Chemical Company, there was added 5 grams of deionized water at 70.degree.
C. and mixed to form a paste. This paste was added to 79.46 grams of water
at 25.degree. C. and thoroughly mixed to obtain a uniform dispersion,
which was then heated 43.degree. C.
Amine citrate complex was prepared by adding 0.65 grams of anhydrous citric
acid to 9.35 grams of melted methyl di(hydrogenated tallow) amine (sold
commercially as Armeen M2HT by Akzo Chemicals Incorporated) corresponding
to a molar ratio of tertiary amine to citric acid of 5.2 to 1 and the
mixture heated till all the citric acid is melted and dissolved in the
amine (approximate temperature: 115.degree. C.). The solution was then
cooled to room temperature where it solidified.
The amine citrate complex plus the unreacted amine was thereafter melted by
heating to about 70.degree. C. and added to the methylcellulose dispersion
described above at 43.degree. C. under gentle agitation to form a smooth,
white emulsion having a cream-like consistency. This emulsion was cooled
to approximately 40.degree. C. and 0.2 grams of Neodol 45-13 (a tradename
for a Shell Chemical Company detergent which is a condensation product of
a mixture of fatty alcohols averaging about 14 to 15 carbon atoms with
about 13 moles of ethylene oxide per mole of alcohol) dissolved in 0.8
grams water was added to it while mixing. The emulsion was gradually
cooled to 25.degree. C. to let the particles solidify.
The particle size of the dispersed phase as determined by a HIAC/ROKO
Particle Size Analyzer (Model PA 720) marketed by Pacific Scientific
Company was about 35 microns mean diameter. Such Analyzer uses established
light blocking principles for measuring the particle size mean diameter
whereby the measured particles interrupt a continuous light beam when
passing through a sensing zone which, in turn, causes a reduction in the
amount of light reaching a photo detector. This technique is particularly
advantageous for measuring particle sizes larger than the normal range of
particles conventionally measured by light scattering techniques.
To this solution there was added, while mixing, 0.6 grams of Neodol 45-13
dissolved in 2.4 grams water followed by 0.35 grams of Neodol 25-3. The
HLB of the emulsion following the addition of these emulsifying agents was
about 12.
A commercial defoaming material (0.02 grams) was then added to the
resulting emulsion followed by the addition of adjuvants such as perfume
(0.5 grams) dye (0.015 grams) and preservative (0.1 gram of Ucarcide
marketed by Union Carbide Corporation), all while mixing. A minor amount
of silicone (0.25 grams of Dow Corning 193) was then added to modify the
viscosity.
The resulting emulsion was highly stable over a temperature range from
ambient to at least 110.degree. F., and, in particular, did not manifest
any particle break down and phase separation when aged at high
temperature, namely a minimum of 24 hours at a temperature of 110.degree.
F. or above.
EXAMPLE 2
A liquid emulsion of the invention was prepared utilizing as the alkyl
cellulose ether a derivative of hydroxyethyl cellulose (HEC) in which the
hydroxyl hydrogen of the ethyl hydroxyl group on the 5th carbon of the
ring is replaced by a fatty alkyl chain having from 10 to 24 carbon atoms.
Such HEC derivative polymers are sold under the trademark "Natrosol Plus"
by Hercules Chemical Company.
An amine-citrate complex was prepared by adding 0.654 gms of anhydrous
citric acid crystals to 9.34 gms of molten methyl-di (hydrogenated tallow)
tertiary amine (sold commercially as Armeen M2HT by Akzo Chemicals, Inc.)
and the mixture was maintained at a temperature of about 115.degree. C.
until the citric acid complexed with the amine. The resulting binary
mixture with excess-free amine was cooled to room temperature under
ambient conditions to obtain a white solid cake.
Deionized water (89.33 gms) was heated to about 48.degree. C. using a bench
top hot plate. Amine-citrate complex (9.994 gms) prepared according to the
aforementioned procedure was melted in a microwave oven and added slowly
to the above hot water under gentle agitation using a paddle mixer. The
mixing was continued for about 10-15 minutes and the resulting milky
emulsion was cooled to 40.degree. C. and maintained at this temperature.
To this amine-citrate emulsion there was then slowly added 0.06 grams of
the above described HEC derivative polymer while maintaining gentle
agitation. The emulsion was mixed for an additional 10 minutes and then
allowed to cool to ambient temperature (approximately 25.degree. C.). To
the above cooled emulsion 0.2 grams of liquid Neodol 25-13 (marketed by
Shell Chemical Company) was added followed by the addition of color and
perfume to complete the prototype preparation. The above method of
preparation resulted in a smooth and milky emulsion having cream like
consistency.
The particle size of the emulsion was measured using Olympus BM-2
microscope and the average particle size was found to be in the range of
15-25 microns. The emulsion did not separate or manifest any particle
disintegration when heated to a temperature of about 110.degree. F. This
was confirmed by a hot-stage video-microscopy. The emulsion was stable
over a range of temperature from ambient to 110.degree. F. The emulsion
was also stable under heat-cool (110.degree. F. to ambient) cycling
conditions.
EXAMPLE 3
To demonstrate the improved stability of a fabric conditioning liquid
emulsion in accordance with the invention, a comparison was made with the
emulsion described in U.S. Pat. No. 4,869,836 to Harmalker, in Example 5,
the disclosure of which is incorporated herein by reference. The fabric
conditioning compositions described in the Harmalker patent are similar to
that described herein except for the absence of an alkyl cellulose ether.
The particle size of an emulsion prepared as set forth in Example 1 above
was measured at room temperature with the HIAC/ROKO particle size
analyzer. The particle size was about 35 microns mean diameter. No change
in particle size was noted after about 24 hours. A second sample of the
same emulsion was maintained at a temperature of about 110.degree. F. for
24 hours and its particle size then measured. The resulting particle size
was unchanged, about 35 microns mean diameter.
By way of comparison, a liquid emulsion was prepared in accordance with
Example 5 of U.S. Pat. No. 4,869,836 and its measured particle size at
room temperature was about 35 microns mean diameter. No change in particle
size was noted after about 24 hours. A second sample of this same emulsion
was maintained at a temperature of about 110.degree. F. for 24 hours and
the resulting measured particle size was below 10 microns mean diameter,
indicating instability of the emulsion at elevated temperatures.
EXAMPLE 4
A commercial granular detergent composition designated herein as Control
"A" was used in this example and had the following composition:
______________________________________
Control A
Component Weight Percent
______________________________________
Linear alkylbenzene sulfonate
4
Sodium fatty alcohol sulfate
9
Sodium ethoxy alcohol sulfate
3
Polyethoxylated alcohol
0.7
Pentasodium tripolyphosphate
31
Sodium pyrophosphate
7
Sodium carbonate 9
Sodium sulfate 16
Sodium silicate 5
Moisture and adjuvants
Balance
______________________________________
The following washing procedure was used to evaluate the efficacy of a
composition in accordance with the invention (the composition of Example
1) and a comparative composition as described in the aforementioned U.S.
Pat. No. 4,869,836, Example 5 thereof. Each of the aforementioned liquid
compositions in an amount of 90 grams was added along with 86 grams of
Control A to a U.S. top-loading washing machine. A 61/2 lb ballast wash
load comprised of cotton and synthetic fabrics was washed with 64 liters
of water at 90.degree. F. using a fourteen minute wash cycle with rinse
and spin operations followed by drying for one hour in an electric dryer.
The washing and drying steps were then repeated and following the second
drying operation the fabrics were evaluated for their anti-static
properties by visual inspection. The terry towels in each wash load were
then equilibrated to 40% humidity overnight and the following day were
evaluated for softness by a six member panel. The results of the static
and softness evaluation for each of the tested compositions is described
in Table 1.
EXAMPLE 5
The physical characteristics of the liquid emulsion of the invention
described in Example 1 was compared with a liquid emulsion not in
accordance with the invention containing a cellulose ether derivative such
as described in U.S. Pat. No. 4,808,086 to Evans et al.
A composition "D" was prepared following the exact procedure of Example 1
except that in place of the Methocel A4C.sup.R of Example 1 present at
0.3% there was substituted Methocel A15LV, a methyl cellulose sold by Dow
Chemical, which is disclosed in U.S. Pat. No. 4,808,086 at Table 1, Column
9 as a soil release agent. The weight present of this methyl cellulose in
the composition was 10%, a concentration substantially below the most
preferred weight range of 25-50% of the fabric conditioning compositions
recommended by the Evans et al patent at col. 1, line 54.
The resulting composition "D" was a non-flowable, non-pourable thick paste.
A second composition "E" was prepared following the exact procedure of
Example 1 except that in place of Methocel A4C.sup.R at 0.3%, there was
substituted Polymer JR-125 which is described in U.S. Pat. No. 4,808,086
at column 2, line 61 as a soil release agent. This polymer was used in the
composition at a weight percent of 10%, below the most preferred weight
range of 25-50% recommended for its use by the Evans et al patent.
The resulting composition "E" was a non-flowable, non-pourable thick paste.
By way of comparison, the liquid emulsion of Example 1 was readily pourable
having a viscosity of about 600 centipoise at room temperature.
TABLE 1
______________________________________
PERFORMANCE OF FABRIC CONDITIONING
COMPOSITIONS OF THE INVENTION
Formulation Softness(a)
Static(b)
______________________________________
Control A -- Very heavy
Control A + comparative composi-
+3 Light to none
tion Of U.S. Pat. No. 4,869,836
Control A + composition of
+4 None
invention (Example 1)
______________________________________
conditions: wash cycle, 90.degree. F. for 14 minutes;
base composition: 84 g of Control A
(a)Softness: difference in softness measured is based on a scale of 1
(very harsh) to 10 (very soft) relative to Control A as evaluated by a
sixmember panel. A difference of one unit or greater is considered
significant. Control A provided a softness of from 3 to 4 when evaluated,
on an absolute basis, on a scale of 1 to 10.
(b)The antistatic properties were characterized visually.
Top